ci: bump fetch-metadata to v3.1.0

Author: nikolay-e

.github/workflows/automerge.yml

@@ -32,7 +32,7 @@ jobs:
     steps:
       - name: Fetch Dependabot metadata
         id: meta
-        uses: dependabot/fetch-metadata@21025c705c08248db411dc16f3619e6b5f9ea21a  # v2.5.0
+        uses: dependabot/fetch-metadata@25dd0e34f4fe68f24cc83900b1fe3fe149efef98  # v3.1.0
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}